Hi Ed, thanks for your reply.

I'm sad to see how BIG problems this is giving me when I at the same time (with very little knowledge in VB) can see how easy it's done with VB.
I hope it is possible to do with VFP ( I think I am getting mad by all these new words like structure, pointer etc ). I really would like to get TYPEs in VFP.

The DRV_GetAddress function is always returning an integer value. So to be able to send either an string or an numeric variable reference i redeclared the DRV_GetAddress a second
time with the alias of DRV_GetAddress_INT ( as you can se in the VFP code below ).

The DeviceHandle-parameter in the code is an integer recieved in an earlier DLL-call (DRV_DeviceOpen)

VB code:

** In modul Driver.bas:

Type PT_DioReadPortByte
Port As Integer
value As Long ' USHORT far *value
End Type

** In modul Global.bas:
Global lpDioReadPort As PT_DioReadPortByte

***************
Private Sub cmdRead_Click()
Dim DiValue As Integer

** The following line returns an integer value .
lpDioReadPort.value = DRV_GetAddress(DiValue)

**Now lpDioReadPort.value can be something like 1242510. Is this the addresslocation of variable DiValue ?

** Right now the value in the variable DiValue is 0
** The next line changes the value in DiValue ( if there is any insignal to the I/O card).
ErrCde = DRV_DioReadPortByte(DeviceHandle, lpDioReadPort) && here the lpDioReadPort must be providing this function with

End Sub
****************

This works perfect in VB, but i can not get the value in variable DiValue to change in VFP.
Can it be something wrong with my setup of the structure lpDioReadPort ?

****************

*My VFP code:

DECLARE INTEGER DRV_GetAddress IN adsapi32.dll as DRV_GetAddress_INT;
INTEGER @ lpVoid

DEFINE CLASS MyStruct_PT_DioReadPortByte AS Struct && Struct.vcx
port = 0
varde = 0
cMembers = " l:port, l:varde "
ENDDEFINE

lpDioReadPort = CREATE("MyStruct_PT_DioReadPortByte")

DiValue=0
tmpstr = ""

** The following line returns an integer value .
lpDioReadPort.varde = DRV_GetAddress_INT(@ DiValue)

tmpstr = lpDioReadPort.GetString()

** The next line does not change the value in variable DiValue as it does in VB.
ErrCde = DRV_DioReadPortByte( DeviceHandle,@ tmpstr )

***********************************

Ed, perhaps you think that i send to much code to you, and if so please tell me.

If someone else want to jump in here, your wellcome.


Torgny